Elicitor-induced rosmarinic acid accumulation and secondary metabolism enzyme activities in Solenostemon scutellarioides

This study aimed to improve rosmarinic acid (RA) production in the whole plant culture of Solenostemon scutellarioides through elicitation. Amongst selected elicitors methyl jasmonate (MJ), salicylic acid (SA), and yeast extract (YE) caused significant elevation in RA accumulation. Elicitation with MJ (50 μM) and SA (50 μM) caused almost 1.7 and 1.4-fold increase in RA accumulation, respectively, within day 1. While YE (100 μg ml^?1) elicitation showed highest RA content (~1.5-fold) in day 3. Preceding the elicitor-induced RA accumulation, there was a notable alteration in the specific activities of RA biosynthetic enzymes viz. phenylalanine ammonia lyase, tyrosine aminotransferase, hydroxyl-phenylpyruvate reductase and rosmarinic acid synthase up on MJ (50 μM), SA (50 μM) and YE (100 mg ml^?1) elicitation. Based on differential responses of aforementioned enzymes, RA synthesis was further scaled up through combination of elicitors in pre-optimized doses. In synergy study, at a time exposure with MJ + SA + YE and MJ + SA followed by YE after 24 h has been found to produce significant elevation of RA (2.0 and 1.9-fold, respectively) within 24 h while later maintained a steady state increased level (~1.7 ± 0.2-fold) over control up to day 7.